U.S. patent number 10,564,463 [Application Number 15/743,394] was granted by the patent office on 2020-02-18 for touch panel-attached display device and method for manufacturing touch panel-attached display device.
This patent grant is currently assigned to SHARP KABUSHIKI KAISHA. The grantee listed for this patent is SHARP KABUSHIKI KAISHA. Invention is credited to Yoshihito Hara, Tetsuya Yamashita.
![](/patent/grant/10564463/US10564463-20200218-D00000.png)
![](/patent/grant/10564463/US10564463-20200218-D00001.png)
![](/patent/grant/10564463/US10564463-20200218-D00002.png)
![](/patent/grant/10564463/US10564463-20200218-D00003.png)
![](/patent/grant/10564463/US10564463-20200218-D00004.png)
![](/patent/grant/10564463/US10564463-20200218-D00005.png)
![](/patent/grant/10564463/US10564463-20200218-D00006.png)
![](/patent/grant/10564463/US10564463-20200218-D00007.png)
![](/patent/grant/10564463/US10564463-20200218-D00008.png)
![](/patent/grant/10564463/US10564463-20200218-D00009.png)
![](/patent/grant/10564463/US10564463-20200218-D00010.png)
View All Diagrams
United States Patent |
10,564,463 |
Yamashita , et al. |
February 18, 2020 |
Touch panel-attached display device and method for manufacturing
touch panel-attached display device
Abstract
To improve sensing sensitivity of a touch panel. A touch
panel-attached display device includes an active matrix substrate
1, a counter substrate, and a liquid crystal layer. On the active
matrix substrate 1, a TFT (display control element) 42, a first
insulating film 44, a plurality of pixel electrodes 31, a second
insulating film 46, and a counter electrode 21 are laminated in
order. In the active matrix substrate 1, a control unit which
detects a touch position by supplying a touch driving signal to a
plurality of counter electrodes 21, and a touch sensor wiring 22
which is formed between the first insulating film 44 and the second
insulating film 46, which connects the control unit and the counter
electrode 21, and which is for supplying the touch driving signal
from the control unit to the counter electrode 21, are also formed.
A thickness of a portion in the second insulating film 46 formed
between the counter electrode 21 and the touch sensor wiring 22 is
thicker than a thickness of a portion formed between the pixel
electrode 31 and the counter electrode 21.
Inventors: |
Yamashita; Tetsuya (Sakai,
JP), Hara; Yoshihito (Sakai, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
SHARP KABUSHIKI KAISHA |
Sakai, Osaka |
N/A |
JP |
|
|
Assignee: |
SHARP KABUSHIKI KAISHA (Sakai,
Osaka, JP)
|
Family
ID: |
58051755 |
Appl.
No.: |
15/743,394 |
Filed: |
August 12, 2016 |
PCT
Filed: |
August 12, 2016 |
PCT No.: |
PCT/JP2016/073700 |
371(c)(1),(2),(4) Date: |
January 10, 2018 |
PCT
Pub. No.: |
WO2017/030080 |
PCT
Pub. Date: |
February 23, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180203280 A1 |
Jul 19, 2018 |
|
Foreign Application Priority Data
|
|
|
|
|
Aug 19, 2015 [JP] |
|
|
2015-161960 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F
3/0412 (20130101); G06F 3/044 (20130101); G02F
1/136286 (20130101); G02F 1/134309 (20130101); G02F
1/1368 (20130101); G06F 3/0446 (20190501); G06F
3/0445 (20190501); G02F 1/13338 (20130101); G02F
2201/123 (20130101); G02F 2001/134372 (20130101); G02F
2201/121 (20130101); G06F 2203/04103 (20130101) |
Current International
Class: |
G02F
1/133 (20060101); G02F 1/1362 (20060101); G06F
3/044 (20060101); G02F 1/1368 (20060101); G02F
1/1343 (20060101); G06F 3/041 (20060101); G06F
3/047 (20060101); G02F 1/1333 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Li; Lin
Attorney, Agent or Firm: ScienBiziP, P.C.
Claims
The invention claimed is:
1. A touch panel-attached display device comprising: an active
matrix substrate; a counter substrate opposing the active matrix
substrate; a liquid crystal layer interposed between the active
matrix substrate and the counter substrate; a display control
element formed on the active matrix substrate; a first insulating
film formed on the active matrix substrate further to the liquid
crystal layer side than the display control element; a plurality of
pixel electrodes formed on the active matrix substrate further to
the liquid crystal layer side than the first insulating film; a
second insulating film formed on the active matrix substrate
further to the liquid crystal layer side than the plurality of
pixel electrodes; a plurality of counter electrodes formed on the
active matrix substrate further to the liquid crystal layer side
than the second insulating film and forming an electrostatic
capacitance between each of the counter electrodes and each of the
pixel electrodes; a control unit which is provided on the active
matrix substrate and which detects a touch position by supplying a
touch driving signal to the plurality of counter electrodes; and a
touch sensor wiring formed between the first insulating film and
the second insulating film, which connects the control unit and the
counter electrode, and which is for supplying the touch driving
signal from the control unit to the counter electrode, wherein, a
thickness of a first portion of the second insulating film formed
between the counter electrode and the touch sensor wiring is
thicker than that of a second portion of the second insulating film
formed between the pixel electrode and the counter electrode.
2. The touch panel-attached display device according to claim 1,
wherein the first portion is formed of two insulating film layers,
and the second portion is formed of one insulating film layer.
3. The touch panel-attached display device according to claim 2,
wherein the two insulating film layers include an insulating film
formed of a first material and an insulating film formed of a
second material having a higher etching rate than that of the first
material, and the insulating film formed of the second material is
formed on the liquid crystal layer side with respect to the
insulating film formed of the first material.
4. The touch panel-attached display device according to claim 3,
wherein the first material is silicon nitride and the second
material is silicon oxide.
5. The touch panel-attached display device according to claim 1,
wherein the first portion is formed of three or more insulating
film layers, and the second portion is formed of one insulating
film layer.
6. The touch panel-attached display device according to claims 1,
further comprising: a conductive film which is provided between the
touch sensor wiring and the first insulating film and is formed of
an identical material as the pixel electrode.
7. The touch panel-attached display device according to claims 1,
further comprising: a planarizing film formed between the first
insulating film and the pixel electrode.
8. The touch panel-attached display device according to claims 1,
further comprising: wherein by making the thickness of the first
portion thicker than the thickness of the second portion, parasitic
capacitance between the touch sensor wiring and the counter
electrode is reduced, compared with a provisional case where the
thickness of the first portion is the same as the thickness of the
second portion.
9. A method for manufacturing a touch panel-attached display device
which is provided with an active matrix substrate, a counter
substrate opposing the active matrix substrate, and a liquid
crystal layer interposed between the active matrix substrate and
the counter substrate, and which has a touch position detection
function, the method comprising: a step of forming a display
control element on the active matrix substrate; a step of forming a
first insulating film so as to cover the display control element
after forming the display control element; a step of forming a
planarizing film so as to cover the first insulating film after
forming the first insulating film; a step of forming a pixel
electrode after forming the planarizing film; a step of forming a
touch sensor wiring for supplying a touch driving signal after
forming the planarizing film; a step of forming a second insulating
film after forming the pixel electrode and the touch sensor wiring;
and a step of forming a counter electrode to be electrically
connected to the touch sensor wiring after forming the second
insulating film, wherein, in the step of forming the second
insulating film, the second insulating film is formed to have a
thickness of a second portion of the second insulating film between
the pixel electrode and the counter electrode which is thinner than
a thickness of a first portion of the second insulating film
between the counter electrode and the touch sensor wiring.
10. The method for manufacturing a touch panel-attached display
device according to claim 9, wherein, in the step of forming the
second insulating film, the second insulating film having a
predetermined thickness is formed between the pixel electrode and
the counter electrode and between the counter electrode and the
touch sensor wiring, and then half-etching of the second insulating
film is performed such that the thickness of the second portion of
the second insulating film between the pixel electrode and the
counter electrode becomes thinner.
11. The method for manufacturing a touch panel-attached display
device according to claim 9, wherein, in the step of forming a
second insulating film, the first layer second insulating film is
formed on the pixel electrode and the touch sensor wiring, a second
layer second insulating film is formed on the first layer second
insulating film, and then the second layer second insulating film
in the second portion is removed by etching.
12. The method for manufacturing a touch panel-attached display
device according to claim 11, wherein the second layer second
insulating film is formed of a material having a higher etching
rate than that of the first layer second insulating film, and in
the step of forming a second insulating film, the first layer
second insulating film and the second layer second insulating film
are formed and then the second layer second insulating film in the
second portion is removed by etching.
13. The method for manufacturing a touch panel-attached display
device according to claim 9, wherein, in the step of forming the
second insulating film, by making the thickness of the second
portion thinner than the thickness of the first portion, the
electrostatic capacitance between the pixel electrode and the
counter electrode is increased, compared with a provisional case
where the thickness of the first portion is the same as the
thickness of the second portion.
Description
TECHNICAL FIELD
The present invention relates to a touch panel-attached display
device and a method for manufacturing the same.
BACKGROUND ART
PTL 1 discloses a touch sensor integrated type display device. In
this touch sensor integrated type display device, a plurality of
common electrodes, which oppose pixel electrodes, also function as
touch driving electrodes and touch sensing electrodes forming the
touch sensor.
CITATION LIST
Patent Literature
PTL 1: Japanese Unexamined Patent Application Publication No.
2015-106411
SUMMARY OF INVENTION
Technical Problem
However, since a touch sensor wiring in the touch sensor integrated
type display device described in PTL 1 is arranged in the same
layer as a gate electrode of a TFT which is a display control
element, that is, at a position far from the panel surface, the
sensing sensitivity of the touch sensor is lowered.
It is an object of the present invention to provide a technique for
improving the sensing sensitivity of a touch panel.
Solution to Problem
A touch panel-attached display device according to an embodiment of
the present invention includes an active matrix substrate, a
counter substrate opposing the active matrix substrate, a liquid
crystal layer interposed between the active matrix substrate and
the counter substrate, a display control element formed on the
active matrix substrate, a first insulating film formed on the
active matrix substrate further to the liquid crystal layer side
than the display control element, a plurality of pixel electrodes
formed on the active matrix substrate further to the liquid crystal
layer side than the first insulating film, a second insulating film
formed on the active matrix substrate further to the liquid crystal
layer side than the plurality of pixel electrodes, a plurality of
counter electrodes formed on the active matrix substrate further to
the liquid crystal layer side than the second insulating film and
forming an electrostatic capacitance between each of the counter
electrodes and each of the pixel electrodes, a control unit which
is provided on the active matrix substrate and which detects a
touch position by supplying a touch driving signal to the plurality
of counter electrodes, and a touch sensor wiring formed between the
first insulating film and the second insulating film, which
connects the control unit and the counter electrode, and which is
for supplying the touch driving signal from the control unit to the
counter electrode, in which, in the second insulating film, a
thickness of a portion formed between the counter electrode and the
touch sensor wiring is thicker than that of a portion formed
between the pixel electrode and the counter electrode.
Advantageous Effects of Invention
According to the disclosure of the present embodiment, the touch
sensor wiring is arranged between the first insulating film and the
second insulating film at a position closer to the surface of the
display device than the layer where the display control element is
formed. Due to this, it is possible to improve the sensing
sensitivity of the touch panel compared to a configuration in which
the touch sensor wiring is arranged in the same layer as the
display control element. In addition, since a thickness of a
portion formed between the counter electrode and the touch sensor
wiring in the second insulating film is thicker than that of a
portion formed between the pixel electrode and the counter
electrode, it is possible to reduce parasitic capacitance between
the counter electrode and the touch sensor wiring. Due to this, it
is possible to improve the sensing sensitivity of the touch
panel.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a cross-sectional diagram of a touch panel-attached
display device according to an embodiment.
FIG. 2 is a diagram showing an example of an arrangement of counter
electrodes formed on an active matrix substrate.
FIG. 3 is an enlarged diagram of a region of a part of the active
matrix substrate.
FIG. 4 is a cross-sectional diagram of the active matrix substrate
in the first embodiment at a position including a TFT, in a portion
in which the counter electrode and a touch sensor wiring are not in
contact.
FIG. 5 is a cross-sectional diagram of the active matrix substrate
in the first embodiment at a position including the TFT, in a
portion in which the counter electrode and the touch sensor wiring
are in contact.
FIG. 6 is a diagram for explaining a manufacturing process of the
touch panel-attached display device according to the first
embodiment.
FIG. 7 is a diagram for explaining a manufacturing process of the
touch panel-attached display device in the first embodiment which
follows the manufacturing process shown in FIG. 6.
FIG. 8 is a diagram for explaining a manufacturing process of the
touch panel-attached display device in the first embodiment which
follows the manufacturing process shown in FIG. 7.
FIG. 9 is a diagram for explaining a manufacturing process
performed after FIG. 7(f) in manufacturing processes of the portion
in which the counter electrode and the touch sensor wiring are in
contact.
FIG. 10 is a cross-sectional diagram of an active matrix substrate
in a second embodiment at a position including a TFT, in a portion
in which a counter electrode and a touch sensor wiring are not in
contact.
FIG. 11 is a cross-sectional diagram of the active matrix substrate
in the second embodiment at a position including the TFT, in a
portion in which the counter electrode and the touch sensor wiring
are in contact.
FIG. 12 is a diagram for explaining a manufacturing process
performed after FIG. 7(f) in the manufacturing processes of the
touch panel-attached display device according to the second
embodiment.
FIG. 13 is a cross-sectional diagram of an active matrix substrate
in a third embodiment at a position including the TFT, in a portion
in which a counter electrode and a touch sensor wiring are not in
contact.
FIG. 14 is a cross-sectional diagram of the active matrix substrate
in the third embodiment at a position including the TFT, in a
portion in which the counter electrode and the touch sensor wiring
are in contact.
FIG. 15 is a diagram for explaining a manufacturing process
performed after FIG. 7(f) in the manufacturing processes of the
touch panel-attached display device in the third embodiment.
FIG. 16 is a cross-sectional diagram of an active matrix substrate
at a position including a TFT in a touch panel-attached display
device in a configuration of modification 1.
FIG. 17 is a cross-sectional diagram of an active matrix substrate
in a configuration of modification 2 at a position including a TFT
in a portion in which a counter electrode and a touch sensor wiring
are not in contact.
FIG. 18 is a cross-sectional diagram of an active matrix substrate
in the configuration of modification 2 at a position including a
TFT in a portion in which the counter electrode and the touch
sensor wiring are in contact.
DESCRIPTION OF EMBODIMENTS
A touch panel-attached display device according to an embodiment of
the present invention is provided with an active matrix substrate;
a counter substrate opposing the active matrix substrate; a liquid
crystal layer interposed between the active matrix substrate and
the counter substrate; a display control element formed on the
active matrix substrate; a first insulating film formed on the
active matrix substrate further to the liquid crystal layer side
than the display control element; a plurality of pixel electrodes
formed on the active matrix substrate further to the liquid crystal
layer side than the first insulating film; a second insulating film
formed on the active matrix substrate further to the liquid crystal
layer side than the plurality of pixel electrodes; a plurality of
counter electrodes formed on the active matrix substrate further to
the liquid crystal layer side than the second insulating film and
forming an electrostatic capacitance between each of the counter
electrodes and each of the pixel electrodes; a control unit which
is provided on the active matrix substrate and which detects a
touch position by supplying a touch driving signal to the plurality
of counter electrodes; and a touch sensor wiring formed between the
first insulating film and the second insulating film, which
connects the control unit and the counter electrode, and which is
for supplying the touch driving signal from the control unit to the
counter electrode, in which, in the second insulating film, a
thickness of a portion formed between the counter electrode and the
touch sensor wiring is thicker than that of a portion formed
between the pixel electrode and the counter electrode (first
configuration).
According to the first configuration, the touch sensor wiring is
arranged between the first insulating film and the second
insulating film and at a position closer to the surface of the
display device than the layer in which the display control element
is formed. Due to this, it is possible to improve the sensing
sensitivity of the touch panel compared to a configuration in which
the touch sensor wiring is arranged in the same layer as the
display control element. In addition, since, in the second
insulating film, a thickness of a portion formed between the
counter electrode and the touch sensor wiring is thicker than that
of a portion formed between the pixel electrode and the counter
electrode, it is possible to reduce the parasitic capacitance
between the counter electrode and the touch sensor wiring. Due to
this, it is possible to improve the sensing sensitivity of the
touch panel. In addition, since the thickness of the second
insulating film between the pixel electrode and the counter
electrode is thin, the capacitance between the pixel electrode and
the counter electrode is increased, which improves the charge
holding property, thus, the display performance is improved.
There may be a configuration (second configuration) in which, in
the first configuration, a portion in the second insulating film,
which is formed between the counter electrode and the touch sensor
wiring, is formed of two insulating film layers, and a portion
formed between the pixel electrode and the counter electrode is
formed of one insulating film layer.
According to the second configuration, it is possible to easily
change the film thickness compared to a configuration in which the
film thickness of the second insulating film formed of one
insulating film layer is changed depending on the location. That
is, since it is sufficient if the portion formed between the
counter electrode and the touch sensor wiring is set to be two
insulating film layers, and the portion formed between the pixel
electrode and the counter electrode is set to be one insulating
film layer, it is possible to easily change the film thickness.
It is possible to have a configuration (third configuration) in
which, in the second configuration, the two insulating film layers
include an insulating film formed of a first material and an
insulating film formed of a second material having a higher etching
rate than that of the first material, and the insulating film
formed of the second material is formed on the liquid crystal layer
side with respect to the insulating film formed of the first
material.
According to the third configuration, by forming the insulating
film formed of the second material with a high etching rate as an
upper layer, after forming the insulating film formed of the first
material and the insulating film formed of the second material, it
is possible to easily remove only the insulating film formed of the
second material with a high etching rate by etching in a portion
between the pixel electrode and the counter electrode.
It is possible to have a configuration (fourth configuration) in
which, in the third configuration, the first material is silicon
nitride and the second material is silicon oxide.
There may be a configuration (fifth configuration) in which, in the
first configuration, a portion in the second insulating film formed
between the counter electrode and the touch sensor wiring is formed
of three or more insulating film layers, and a portion formed
between the pixel electrode and the counter electrode is formed of
one insulating film layer.
According to the fifth configuration, since it is possible to
increase the thickness of the second insulating film between the
counter electrode and the touch sensor wiring, parasitic
capacitance between the counter electrode and the touch sensor
wiring is further reduced and it is possible to further improve the
sensing sensitivity of the touch panel.
There may be a configuration (sixth configuration) in which any one
of the first to fifth configurations further includes a conductive
film which is provided between the touch sensor wiring and the
first insulating film and is formed of an identical material as the
pixel electrode.
According to the sixth configuration, providing a conductive film
formed of the same material as the pixel electrode between the
touch sensor wiring and the first insulating film makes it possible
to improve the adhesion between the touch sensor wiring and the
first insulating film.
There may be a configuration (seventh configuration) in which any
one of the first to sixth configurations is further provided with a
planarizing film formed between the first insulating film and the
pixel electrode.
Providing the planarizing film makes it possible to widen the
interval between the touch sensor wiring and the gate wiring and
the source wiring. Due to this, since it is possible to further
reduce parasitic capacitance between the touch sensor wiring and
the gate wiring and the source wiring, it is possible to further
improve the sensing sensitivity of the touch panel.
A method for manufacturing a touch panel-attached display device
according to an embodiment of the present invention is a method for
manufacturing a touch panel-attached display device which is
provided with an active matrix substrate, a counter substrate
opposing the active matrix substrate, and a liquid crystal layer
interposed between the active matrix substrate and the counter
substrate, and which has a touch position detection function, the
method including a step of forming a display control element on the
active matrix substrate; a step of forming a first insulating film
so as to cover the display control element after forming the
display control element; a step of forming a planarizing film so as
to cover the first insulating film after forming the first
insulating film; a step of forming a pixel electrode after forming
the planarizing film; a step of forming a touch sensor wiring for
supplying a touch driving signal after forming the planarizing
film; a step of forming a second insulating film after forming the
pixel electrode and the touch sensor wiring; and a step of forming
a counter electrode to be electrically connected to the touch
sensor wiring after forming the second insulating film, in which,
in the step of forming a second insulating film, the second
insulating film is formed to have a thickness between the pixel
electrode and the counter electrode which is thinner than a
thickness between the counter electrode and the touch sensor wiring
(eighth configuration).
According to the eighth configuration, the touch sensor wiring is
arranged between the planarizing film and the second insulating
film, at a position closer to the surface of the display device
than the layer in which the display control element is formed. Due
to this, it is possible to improve the sensing sensitivity of the
touch panel compared to a configuration in which the touch sensor
wiring is arranged in the same layer as the display control
element. In addition, since, in the second insulating film, a
thickness of a portion formed between the counter electrode and the
touch sensor wiring is thicker than that of a portion formed
between the pixel electrode and the counter electrode, it is
possible to reduce parasitic capacitance between the counter
electrode and the touch sensor wiring. Due to this, it is possible
to improve the sensing sensitivity of the touch panel. In addition,
since the thickness of the second insulating film between the pixel
electrode and the counter electrode is thin, the capacitance
between the pixel electrode and the counter electrode is increased,
which improves the charge holding property, thus, the display
performance is improved.
In the step of forming a second insulating film in the eighth
configuration, the second insulating film having a predetermined
thickness may be formed (ninth configuration) between the pixel
electrode and the counter electrode and between the counter
electrode and the touch sensor wiring, and then half-etching may be
performed such that the thickness of the second insulating film
between the pixel electrode and the counter electrode becomes
thinner.
According to the ninth configuration, it is possible to change the
film thickness of the second insulating film between the pixel
electrode and the counter electrode and of the second insulating
film between the counter electrode and the touch sensor wiring by
half-etching.
In the step of forming a second insulating film in the eighth
configuration, a first layer second insulating film may be formed,
a second layer second insulating film may be formed on the first
layer second insulating film, and then the first layer second
insulating film between the pixel electrode and the counter
electrode may be removed by etching (tenth configuration).
According to the tenth configuration, since it is sufficient to
remove the first layer second insulating film by etching when
thinning the thickness of the second insulating film between the
pixel electrode and the counter electrode, it is possible to easily
thin the thickness of the second insulating film between the pixel
electrode and the counter electrode.
It is possible to, in the tenth configuration, form the second
layer second insulating film of a material having a higher etching
rate than that of the first layer second insulating film and, in
the step of forming a second insulating film, to form the first
layer second insulating film and the second layer second insulating
film and then remove the second layer second insulating film
between the pixel electrode and the counter electrode by etching
(eleventh configuration).
According to the eleventh configuration, it is possible to easily
remove the second layer second insulating film formed of a material
with a high etching rate by etching between the pixel electrode and
the counter electrode.
[Embodiments]
A detailed description will be given below of embodiments of the
present invention with reference to the drawings. In the drawings,
the same or corresponding parts are denoted by the same reference
numerals, and description thereof will not be repeated. Here, for
ease of explanation, configurations are simplified or schematically
shown in the drawings referred to below and some constituent
members are omitted. In addition, the dimensional ratios between
the constituent members shown in each drawing do not necessarily
indicate the actual size ratios.
[First Embodiment]
FIG. 1 is a cross-sectional diagram of a touch panel-attached
display device 10 according to one embodiment. The touch
panel-attached display device 10 according to one embodiment is
provided with an active matrix substrate 1, a counter substrate 2,
and a liquid crystal layer 3 interposed between the active matrix
substrate 1 and the counter substrate 2. Each of the active matrix
substrate 1 and the counter substrate 2 is provided with a glass
substrate which is substantially transparent (having a high
light-transmitting property). The counter substrate 2 is provided
with a color filter (not shown). In addition, although not shown,
the touch panel-attached display device 10 is provided with a
backlight.
The touch panel-attached display device 10 according to the present
embodiment has a function of displaying an image and also has a
function of detecting position information (touch position)
inputted by a user based on the displayed image. The touch
panel-attached display device 10 is provided with a so-called
in-cell type touch panel in which wiring and the like necessary for
detecting the touch position are formed in the display panel.
In the touch panel-attached display device 10 according to the
present embodiment, the driving method of liquid crystal molecules
included in the liquid crystal layer 3 is a lateral electric field
driving method. In order to realize the lateral electric field
driving method, a pixel electrode and a counter electrode (may also
be referred to as a common electrode) for forming an electric field
are formed in the active matrix substrate 1.
FIG. 2 is a diagram showing an example of the arrangement of
counter electrodes 21 formed on the active matrix substrate 1. The
counter electrodes 21 are formed on the surface of the active
matrix substrate 1 on the liquid crystal layer 3 side. As shown in
FIG. 2, the counter electrodes 21 have a rectangular shape and a
plurality of the counter electrodes 21 are arranged in a matrix on
the active matrix substrate 1.
A controller (control unit) 20 is provided on the active matrix
substrate 1. The controller 20 performs control for displaying an
image and also performs control for detecting a touch position.
The controller 20 and each counter electrode 21 are connected by a
touch sensor wiring 22 extending in the Y axis direction. That is,
touch sensor wirings 22 equal in number to the number of the
counter electrodes 21 are formed on the active matrix substrate
1.
In the touch panel-attached display device 10 according to the
present embodiment, the counter electrode 21 may be used for image
display control and may also be used for touch position detection
control by forming an electrostatic capacitance in a pair with the
pixel electrode.
Parasitic capacitance is formed between the counter electrode 21
and the adjacent counter electrode 21 or the like; however, when a
human finger or the like touches the display screen of the display
device 10, a capacitance is formed between the counter electrode 21
and the human finger or the like, thus the electrostatic
capacitance increases. At the time of the touch position detection
control, the controller 20 supplies a touch driving signal to the
counter electrode 21 via the touch sensor wiring 22, and receives a
touch detection signal via the touch sensor wiring 22. As a result,
a change in the electrostatic capacitance is detected, whereby a
touch position is detected. That is, the touch sensor wiring 22
functions as a line for transmitting and receiving the touch
driving signal and the touch detection signal.
FIG. 3 is an enlarged diagram of a region of a part of the active
matrix substrate 1. As shown in FIG. 3, a plurality of pixel
electrodes 31 are arranged in a matrix. In addition, although not
shown in FIG. 3, thin film transistors (TFT) which are display
control elements are also arranged in a matrix corresponding to the
pixel electrodes 31. Here, the counter electrode 21 is provided
with a plurality of slits 21a.
Gate wirings 32 and source wirings 33 are provided around the pixel
electrodes 31. The gate wirings 32 extend in the X axis direction
and a plurality of gate wirings 32 are provided at predetermined
intervals in the Y axis direction. The source wirings 33 extend in
the Y axis direction and a plurality of source wirings 33 are
provided at predetermined intervals in the X axis direction. That
is, the gate wirings 32 and the source wirings 33 are formed in a
lattice shape and the pixel electrodes 31 are provided in regions
partitioned by the gate wirings 32 and the source wirings 33.
As shown in FIG. 3, the touch sensor wirings 22 extending in the Y
axis direction are arranged such that parts thereof overlap with
the source wirings 33 extending in the Y axis direction in the
normal direction of the active matrix substrate 1. Specifically,
the touch sensor wirings 22 are provided in a higher layer than the
source wiring 33 and parts of the touch sensor wirings 22 and the
source wirings 33 overlap in plan view.
Here, in FIG. 3, white circles 35 indicate portions to which the
counter electrode 21 and the touch sensor wiring 22 are
connected.
FIG. 4 and FIG. 5 are cross-sectional diagrams of the active matrix
substrate 1 at the position including a TFT 42 in the first
embodiment. FIG. 4 is a cross-sectional diagram of a portion in
which the counter electrode 21 and the touch sensor wiring 22 are
not in contact. FIG. 5 is a cross-sectional diagram of a portion in
which the counter electrode 21 and the touch sensor wiring 22 are
in contact.
The TFT 42 is provided as a display control element on a glass
substrate 40. The TFT 42 includes a gate electrode 42a, a
semiconductor film 42b, a source electrode 42c, and a drain
electrode 42d.
The gate electrode 42a of the TFT 42 is formed on the glass
substrate 40. The gate electrode 42a is formed of a laminated film
of titanium (Ti) and copper (Cu), for example. Although not shown
in FIG. 4 and FIG. 5, the gate wiring 32 is also formed on the
glass substrate 40 in the same layer as the layer in which the gate
electrode 42a is formed.
A gate insulating film 43 is formed so as to cover the gate
electrode 42a. The gate insulating film 43 is formed of, for
example, silicon nitride (SiNx) or silicon dioxide (SiO.sub.2).
The semiconductor film 42b is formed on the gate insulating film
43. The semiconductor film 42b is, for example, an oxide
semiconductor film and may include at least one kind of metal
element from among In, Ga, and Zn. In the present embodiment, the
semiconductor film 42b includes, for example, an
In--Ga--Zn--O-based semiconductor. Here, the In--Ga--Zn--O-based
semiconductor is a ternary oxide of In (indium), Ga (gallium), Zn
(zinc), and the ratio (composition ratio) of In, Ga, and Zn is not
particularly limited and includes, for example, In:Ga:Zn=2:2:1,
In:Ga:Zn=1:1:1, In:Ga:Zn=1:1:2, and the like.
The source electrode 42c and the drain electrode 42d are provided
on the semiconductor film 42b so as to be separated from each
other. The source electrode 42c and the drain electrode 42d are,
for example, formed of a laminated film of titanium (Ti) and copper
(Cu). Although not shown in FIG. 4 and FIG. 5, the source wiring 33
is formed in the same layer as the layer in which the source
electrode 42c is formed.
A first insulating film 44 is formed so as to cover the source
electrode 42c and the drain electrode 42d. The first insulating
film 44 is formed of, for example, silicon nitride (SiNx) or
silicon dioxide (SiO.sub.2).
A planarizing film 45 is formed as an insulator on the first
insulating film 44. The planarizing film 45 is formed of, for
example, an acrylic resin material such as polymethylmethacrylate
resin (PMMA). It is also possible to omit the planarizing film
45.
A pixel electrode 31 is formed on the planarizing film 45. The
pixel electrode 31 is a transparent electrode and is formed of a
material such as ITO (Indium Tin Oxide), ZnO (Zinc Oxide), IZO
(Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), and ITZO
(Indium Tin Zinc Oxide).
A conductive film 47 is also formed on the planarizing film 45. The
conductive film 47 is a transparent electrode film formed of the
same material as the pixel electrode 31 and is provided to improve
the adhesion between the touch sensor wiring 22 and the planarizing
film 45. Therefore, it is possible to omit the conductive film 47
in a case where the adhesion between the touch sensor wiring 22 and
the planarizing film 45 is high.
The touch sensor wiring 22 is formed on the conductive film 47. For
example, the touch sensor wiring 22 is formed of any one of copper
(Cu), titanium (Ti), molybdenum (Mo), aluminum (Al), magnesium
(Mg), cobalt (Co), chromium (Cr), tungsten (W), cadmium (Cd), or a
mixture thereof. In a case where the conductive film 47 is omitted,
the touch sensor wiring 22 is formed on the planarizing film
45.
The second insulating film 46 is formed so as to cover the pixel
electrode 31 and the touch sensor wiring 22. The second insulating
film 46 is made of, for example, silicon nitride (SiNx) or silicon
dioxide (SiO.sub.2).
The counter electrodes 21 are formed on the second insulating film
46. In a portion in which the counter electrode 21 and the touch
sensor wiring 22 are connected, an opening 461 is provided in the
second insulating film 46, and in the opening 461 portion, the
counter electrodes 21 are in contact with the touch sensor wiring
22 (refer to FIG. 5). The counter electrodes 21 are transparent
electrodes and are formed of a material such as, for example, ITO,
ZnO, IZO, IGZO, ITZO, or the like.
A contact hole CH1 is formed in the first insulating film 44 and
the planarizing film 45. The pixel electrode 31 is in contact with
the drain electrode 42d of the TFT 42 via the contact hole CH1.
In the present embodiment, as shown in FIG. 4 and FIG. 5, the touch
sensor wiring 22 is formed on the planarizing film 45, more
specifically, on the conductive film 47. That is, since the touch
sensor wiring 22 is arranged at a position close to the panel
surface, the sensing sensitivity of the touch sensor is increased
compared to a configuration in which the touch sensor wiring is
formed in the layer where the TFT 42 is formed, such as the layer
in which the gate wiring 32 is formed or the layer in which the
source wiring 33 is formed.
In addition, when the touch sensor wiring is formed in the layer in
which the gate wiring 32 is formed or in the layer in which the
source wiring 33 is formed, since the touch sensor wiring is close
to the gate wiring 32 and the source wiring 33, the parasitic
capacitance becomes large, and there is a possibility that the
sensing sensitivity of the touch panel will be lowered. However, in
the present embodiment, since the touch sensor wiring 22 is
arranged via the first insulating film 44 and the planarizing film
45 with respect to the gate wiring 32 and the source wiring 33,
parasitic capacitance between the touch sensor wiring 22 and the
gate wiring 32 and the source wiring 33 is small, and it is
possible to suppress a decrease in the sensing sensitivity of the
touch panel.
Furthermore, as shown in FIG. 4 and FIG. 5, since the touch sensor
wiring 22 is formed so as to partially overlap with the gate
electrode 42a, the transmittance does not decrease significantly.
For example, when the touch sensor wiring is formed in the same
layer as the layer in which the gate electrode 42a is formed, the
transmittance decreases in accordance with the touch sensor wiring;
however, according to the configuration of the present embodiment,
it is possible to improve the transmittance compared to a
configuration in which the touch sensor wiring is formed in the
same layer as the gate electrode 42a.
Here, in the present embodiment, the thickness of the second
insulating film 46 is different between the position where the
touch sensor wiring 22 is provided and the position where the pixel
electrode 31 is provided. Specifically, a thickness H1 of the
second insulating film 46 between the touch sensor wiring 22 and
the counter electrode 21 is larger than a thickness H2 of the
second insulating film 46 between the pixel electrode 31 and the
counter electrode 21. As an example, the thickness H1 of the second
insulating film 46 between the touch sensor wiring 22 and the
counter electrode 21 is 200 nm, and the thickness H2 of the second
insulating film 46 between the pixel electrode 31 and the counter
electrode 21 is 100 nm.
Increasing the thickness H1 of the second insulating film 46
between the touch sensor wiring 22 and the counter electrode 21
reduces parasitic capacitance between the touch sensor wiring 22
and the counter electrode 21 and makes it possible to improve the
sensing sensitivity of the touch panel. In addition, reducing the
thickness H2 of the second insulating film 46 between the pixel
electrode 31 and the counter electrode 21 increases the capacitance
between the pixel electrode 31 and the counter electrode 21 to
improve the charge holding property, whereby it is possible to
improve the display performance.
FIG. 6 to FIG. 8 are diagrams for explaining a manufacturing
process of the touch panel-attached display device 10 according to
the first embodiment.
The TFT 42 is formed on the glass substrate 40 by a known method.
FIG. 6(a) shows a state in which the TFT 42 is formed on the glass
substrate 40 by a known method and the first insulating film 44 and
the planarizing film 45 are formed thereon. A hole is formed in the
planarizing film 45 to form the contact hole CH1 which connects the
pixel electrode 31 and the drain electrode 42d of the TFT42.
From the state shown in FIG. 6(a), a plasma treatment using
nitrogen gas or oxygen gas is performed on the exposed surface
(refer to FIG. 6(b)). That is, plasma treatment is performed on the
exposed surfaces of the first insulating film 44 and the
planarizing film 45. Performing the plasma treatment makes it
possible to form fine irregularities on the smooth surface (surface
roughening) and to improve the adhesion at the time of forming the
transparent electrode film in the subsequent step.
Next, a mask 61 is formed on the surface of the planarizing film 45
using a photoresist (refer to FIG. 6(c)). Then, the first
insulating film 44 not covered with the mask 61 is dry-etched to
form the contact hole CH1 (refer to FIG. 6(d)). Thereafter, the
mask 61 is peeled off (refer to FIG. 6(e)).
Subsequently, a transparent electrode film 62 for forming the pixel
electrode 31 and the conductive film 47 is formed, and a metal film
63 for forming the touch sensor wiring 22 is formed thereon (refer
to FIG. 6(f)). The thickness of the transparent electrode film 62
is, for example, 10 nm to 150 nm. In addition, the thickness of the
metal film 63 is, for example, 50 nm to 300 nm.
Subsequently, a mask 71 is formed on the metal film 63 using a
photoresist (refer to FIG. 7(a)). The mask 71 is formed in a region
for forming the pixel electrode 31 and a region for forming the
touch sensor wiring 22. Subsequently, the transparent electrode
film 62 and the metal film 63 in a region not covered with the mask
71 are wet-etched (refer to FIG. 7(b)).
Then, the mask 71 is peeled off (refer to FIG. 7(c)).
Next, a mask 72 is formed using a photoresist on the metal film 63
which is the touch sensor wiring 22 in the region where the metal
film 63 is formed (refer to FIG. 7(d)). Then, the metal film 63 not
covered with the mask 72 is removed by wet etching (refer to FIG.
7(e)). Thereafter, the mask 72 is peeled off (refer to FIG. 7(f)).
Due to this, the pixel electrode 31, the conductive film 47, and
touch sensor wiring 22 are formed.
Subsequently, the second insulating film 46 is formed (refer to
FIG. 8(a)). The thickness of the second insulating film 46 is, for
example, 200 to 400 nm.
Subsequently, after forming a photoresist film on the surface of
the second insulating film 46, the portion in which the touch
sensor wiring 22 is formed is exposed normally and the portion in
which the pixel electrode 31 is formed is exposed with a half
exposure. Thereafter, an ashing treatment is performed in order to
set the film thickness of the photoresist film to a desired
thickness. Due to this, the mask 72 is formed in which the film
thickness of the portion in which the touch sensor wiring 22 is
formed is thick, and the film thickness of the portion in which the
pixel electrode 31 is formed is thin (refer to FIG. 8(b)).
Subsequently, dry etching is performed. As the etching gas, it is
possible to use, for example, SF.sub.6 gas or CF.sub.4 gas. Since
the mask 72 in the portion in which the touch sensor wiring 22 is
formed is thick, the second insulating film 46 in this portion
remains as it is without being etched. On the other hand, since the
mask 72 is thin in the portion in which the pixel electrode 31 is
formed, only part of the thickness of the second insulating film 46
is removed in this portion (refer to FIG. 8(c)). That is, in the
portion in which the pixel electrode 31 is formed, half-etching is
performed, in which a part of the thickness of the second
insulating film 46 is removed. In the half-etching, for example,
half the thickness of the second insulating film 46 being formed is
removed.
After peeling off the mask 72, a transparent electrode film for
forming the counter electrode 21 is formed (refer to FIG.
8(d)).
FIG. 6 to FIG. 8 illustrate the manufacturing process of the
portion in which the counter electrode 21 and the touch sensor
wiring 22 are not in contact with each other, but the manufacturing
process of the portion in which the counter electrode 21 and the
touch sensor wiring 22 are in contact is the same. A description
will be given of the manufacturing process performed after FIG.
7(f) in the manufacturing processes of the portion in which the
counter electrode 21 and the touch sensor wiring 22 are in contact
with each other with reference to FIG. 9.
After the step of FIG. 7(f), the second insulating film 46 is
formed (refer to FIG. 9(a)).
Subsequently, a photoresist film is formed on the surface of the
second insulating film 46, the portion in which the touch sensor
wiring 22 is formed is exposed normally, the portion in which the
pixel electrode 31 is formed is exposed with a half exposure, and
then an ashing treatment is performed in order to set the thickness
of the photoresist film to a desired thickness. Due to this, the
mask 72 is formed in which the portion in which the touch sensor
wiring 22 is formed is thick, and the portion in which the pixel
electrode 31 is formed is thin. However, in the portion in which
the touch sensor wiring 22 is formed, the mask 72 is formed by
carrying out exposure such that the mask 72 is not formed in a
region for connecting the touch sensor wiring 22 and the counter
electrode 21 to be formed in a later process (refer to FIG.
9(b)).
Subsequently, dry etching is performed. Since the mask 72 in the
portion in which the touch sensor wiring 22 is formed is thick, the
second insulating film 46 in this portion remains as it is without
being etched. On the other hand, since the mask 72 in the portion
in which the pixel electrode 31 is formed is thin, only part of the
thickness of the second insulating film 46 in this portion is
removed (half-etching). In addition, the second insulating film 46
in the region above the touch sensor wiring 22 where the mask 72 is
not formed is entirely removed by etching (refer to FIG. 9(c)).
After peeling off the mask 72, a transparent electrode film for
forming the counter electrode 21 is formed (refer to FIG. 9(d)).
Due to this, the touch sensor wiring 22 and the counter electrode
21 are electrically connected.
[Second Embodiment]
FIG. 10 and FIG. 11 are cross-sectional diagrams of the active
matrix substrate 1 at the position including the TFT 42 in the
second embodiment. FIG. 10 is a cross-sectional diagram of a
portion in which the counter electrode 21 and the touch sensor
wiring 22 are not in contact. FIG. 11 is a cross-sectional diagram
of a portion in which the counter electrode 21 and the touch sensor
wiring 22 are in contact.
In the present embodiment as well, in the same manner as the first
embodiment, the thickness of the second insulating film 46 between
the touch sensor wiring 22 and the counter electrode 21 is thicker
than the thickness of the second insulating film 46 between the
pixel electrode 31 and the counter electrode 21. However, the
second insulating film 46 between the touch sensor wiring 22 and
the counter electrode 21 is formed of two insulating film layers of
an insulating film 46a formed of a first material and an insulating
film 46b formed of a second material. In addition, the second
insulating film 46 between the pixel electrode 31 and the counter
electrode 21 is formed of one insulating film layer which is the
insulating film 46a formed of a first material.
The second material is a material having a higher etching rate than
the first material. For example, the second material is SiNx
(silicon nitride) and the first material is SiO.sub.2 (silicon
dioxide). The film thickness of the insulating film 46b in a case
where SiNx is used as the second material is, for example, 50 nm to
500 nm. In addition, the film thickness of the insulating film 46a
in a case where SiO2 is used as the first material is, for example,
50 to 200 nm. However, the second material is not limited to SiNx
and the first material is not limited to SiO.sub.2.
In the manufacturing processes of the touch panel-attached display
device 10 in the second embodiment, the manufacturing processes
from FIG. 6(a) to FIG. 7(f) are the same as those in the first
embodiment. Accordingly, a description will be given of the
manufacturing process performed after FIG. 7(f) with reference to
FIG. 12. In FIG. 12, the left side is a cross-sectional diagram for
explaining the manufacturing process of the portion in which the
counter electrode 21 and the touch sensor wiring 22 are not in
contact, and the right side is a cross-sectional diagram for
explaining the manufacturing process of the portion in which the
counter electrode 21 and the touch sensor wiring 22 are in
contact.
When the process shown in FIG. 7(f) is finished, the insulating
film 46a formed of a first material is formed so as to cover the
pixel electrode 31 and the touch sensor wiring 22, and the
insulating film 46b formed of a second material is formed thereon
(refer to FIG. 12(a)).
Subsequently, after a photoresist film is formed on the surface of
the insulating film 46b formed of the second material, a portion in
which the touch sensor wiring 22 is formed is exposed normally and
a portion in which the pixel electrode 31 is formed is exposed with
a half exposure. Thereafter, an ashing treatment is performed in
order to set the film thickness of the photoresist film to a
desired thickness. Due to this, the mask 72 is formed in which the
film thickness of the portion in which the touch sensor wiring 22
is formed is thick, and the film thickness of the portion in which
the pixel electrode 31 is formed is thin (refer to FIG. 12(b)). In
a portion in which the touch sensor wiring 22 and the counter
electrode 21 are in contact, exposure is carried out such that the
mask 72 is not formed in a region for connecting the touch sensor
wiring 22 and the counter electrode 21 to be formed in a later
process in the portion in which the touch sensor wiring 22 is
formed (refer to the cross-sectional diagram on the right side of
FIG. 12(b)).
Subsequently, dry etching is performed. As the etching gas, it is
possible to use SF.sub.6 gas or CF.sub.4 gas, for example. Since
the mask 72 in the portion in which the touch sensor wiring 22 is
formed is thick, the second insulating film 46 in this portion
remains as it is without being etched. On the other hand, since the
mask 72 in the portion in which the pixel electrode 31 is formed is
thin, only the upper layer of the insulating film 46b formed of the
second material is removed in this portion (refer to FIG. 12(c)).
That is, in the portion in which the pixel electrode 31 is formed,
half-etching is performed in which only the insulating film 46b
formed of the second material is removed out of the insulating film
46a formed of the first material and the insulating film 46b formed
of the second material.
In addition, in the region above the touch sensor wiring 22 where
the mask 72 is not formed, the insulating film 46b formed of the
second material and the insulating film 46a formed of the first
material are removed by etching (refer to the cross-sectional
diagram on the right side of FIG. 12(c)).
In the present embodiment, the second insulating film 46 has a
two-layer structure of the insulating film 46a formed of a first
material and the insulating film 46b formed of a second material
and the insulating film 46b formed of a second material having a
high etching rate compared to the insulating film 46a formed of a
first material is formed on the upper layer (the liquid crystal
layer 3 side). Due to this, it is possible to easily remove only
the insulating film 46b formed of the second material having a high
etching rate by half-etching.
After peeling off the mask 72, a transparent electrode film for
forming the counter electrode 21 is formed (refer to FIG.
12(d)).
[Third Embodiment]
FIG. 13 and FIG. 14 are cross-sectional diagrams of the active
matrix substrate 1 at the position including the TFT 42 in the
third embodiment. FIG. 13 is a cross-sectional diagram of a portion
in which the counter electrode 21 and the touch sensor wiring 22
are not in contact. FIG. 14 is a cross-sectional diagram of a
portion in which the counter electrode 21 and the touch sensor
wiring 22 are in contact.
In the present embodiment as well, in the same manner as the first
and second embodiments, the thickness of the second insulating film
46 between the touch sensor wiring 22 and the counter electrode 21
is thicker than the thickness of the second insulating film 46
between the pixel electrode 31 and the counter electrode 21.
However, the second insulating film 46 between the touch sensor
wiring 22 and the counter electrode 21 is formed of three
insulating film layers, which are an insulating film 46c formed of
a first material, an insulating film 46d formed of a second
material, and an insulating film 46e formed of a third material. In
addition, the second insulating film 46 between the pixel electrode
31 and the counter electrode 21 is formed of one insulating film
layer, which is the insulating film 46c formed of the first
material.
In the same manner as the second embodiment, the second material is
a material having a higher etching rate than the first material.
For example, the second material is SiNx and the first material is
SiO.sub.2. In addition, the third material is, for example,
SiO.sub.2. The film thickness of the insulating film 46c in a case
where SiO.sub.2 is used as the first material is, for example, 50
to 200 nm. The film thickness of the insulating film 46d in a case
where SiNx is used as the second material is, for example, 50 nm to
500 nm. The film thickness of the insulating film 46e in a case
where SiO.sub.2 is used as the third material is, for example, 50
to 200 nm. However, the first material is not limited to SiO.sub.2,
and the second material is not limited to SiNx. In addition, the
third material is not limited to SiO.sub.2.
In the manufacturing processes of the touch panel-attached display
device 10 according to the third embodiment, the manufacturing
processes from FIG. 6(a) to FIG. 7(f) are the same as those in the
first embodiment. Accordingly, a description will be given of the
manufacturing process performed after FIG. 7(f) with reference to
FIG. 15. In FIG. 15, the left side is a cross-sectional diagram for
explaining the manufacturing process of the portion in which the
counter electrode 21 and the touch sensor wiring 22 are not in
contact, and the right side is a cross-sectional diagram for
explaining the manufacturing process of the portion in which the
counter electrode 21 and the touch sensor wiring 22 are in
contact.
When the process shown in FIG. 7(f) is finished, the insulating
film 46c formed of a first material is formed so as to cover the
pixel electrode 31 and the touch sensor wiring 22. Subsequently,
the insulating film 46d formed of a second material is formed on
the insulating film 46c, and the insulating film 46e formed of a
third material is formed on the insulating film 46d (refer to FIG.
15(a)).
Subsequently, after a photoresist film is formed on the surface of
the insulating film 46e formed of the third material, a portion in
which the touch sensor wiring 22 is formed is exposed normally and
a portion in which the pixel electrode 31 is formed is exposed with
a half exposure. Thereafter, an ashing treatment is performed in
order to set the film thickness of the photoresist film to a
desired thickness. Due to this, the mask 72 is formed in which the
film thickness of the portion in which the touch sensor wiring 22
is formed is thick, and the film thickness of the portion in which
the pixel electrode 31 is formed is thin (refer to FIG. 15(b)). In
a portion in which the touch sensor wiring 22 and the counter
electrode 21 are in contact, exposure is carried out such that the
mask 72 is not formed in a region for connecting the touch sensor
wiring 22 and the counter electrode 21 to be formed in a later
process in the portion in which the touch sensor wiring 22 is
formed (refer to the cross-sectional diagram on the right side of
FIG. 15(b)).
Subsequently, dry etching is performed. As the etching gas, it is
possible to use SF.sub.6 gas or CF.sub.4 gas, for example. Since
the mask 72 in the portion in which the touch sensor wiring 22 is
formed is thick, the second insulating film 46 in this portion
remains as it is without being etched. On the other hand, since the
mask 72 in the portion in which the pixel electrode 31 is formed is
thin, the insulating film 46d formed of the second material and the
insulating film 46e formed of the third material are removed in
this portion (refer to FIG. 15(c)). That is, in the portion in
which the pixel electrode 31 is formed, half-etching is performed
in which only the insulating film 46d formed of the second material
and the insulating film 46e formed of the third material are
removed from among the insulating film 46c formed of the first
material, the insulating film 46d formed of the second material,
and the insulating film 46e formed of the third material.
In addition, in the region above the touch sensor wiring 22 where
the mask 72 is not formed, the insulating film 46c formed of the
first material, the insulating film 46d formed of the second
material, and the insulating film 46e formed of the third material
are removed by etching (refer to the cross-sectional diagram on the
right side of FIG. 15(c)).
In the present embodiment, the second insulating film 46 has a
three-layer structure of the insulating film 46c formed of a first
material, the insulating film 46d formed of a second material, and
the insulating film 46e formed of a third material, and the
insulating film 46d formed of a second material having a high
etching rate is formed on the insulating film 46c formed of the
first material which is the lowermost layer. Due to this, leaving
only the insulating film 46a formed of the first material which is
the lowermost layer by half-etching makes it possible to easily
remove only the insulating film 46d formed of the second material
and the insulating film 46e formed of the third material, which
have a high etching rate.
Subsequently, after peeling off the mask 72, a transparent
electrode film for forming the counter electrode 21 is formed
(refer to FIG. 15(d)).
According to the present embodiment, since the second insulating
film 46 between the touch sensor wiring 22 and the counter
electrode 21 has a three-layer structure of the insulating film 46c
formed of the first material, the insulating film 46d formed of the
second material, and the insulating film 46e formed of the third
material, it is possible to further reduce parasitic capacitance
between the touch sensor wiring and the counter electrode 21,
compared to the first and second embodiments. Due to this, it is
possible to further improve the sensing sensitivity of the touch
panel.
It is possible for the touch panel-attached display device 10
according to the present embodiment to have various modified
configurations.
[Modification 1]
FIG. 16 is a cross-sectional diagram of the active matrix substrate
1 at a position including a TFT in a touch panel-attached display
device 10A in the configuration of modification 1. In the
configuration of modification 1, an etch stopper layer 161 is
provided on the semiconductor film 42b of the TFT 42 and between
the source electrode 42c and the drain electrode 42d. Providing the
etch stopper layer 161 makes it possible to prevent the
semiconductor film 42b from being damaged by etching during the
formation of the source electrode 42c and the drain electrode
42d.
[Modification 2]
FIG. 17 and FIG. 18 are cross-sectional diagrams of the active
matrix substrate 1 at the position including the TFT in a touch
panel-attached display device 10B in the configuration of
modification 2. FIG. 17 is a cross-sectional diagram of a portion
in which the counter electrode 21 and the touch sensor wiring 22
are not in contact. FIG. 18 is a cross-sectional diagram of a
portion in which the counter electrode 21 and the touch sensor
wiring 22 are in contact. In the configuration of modification 2,
as shown in FIG. 17 and FIG. 18, the line width of the touch sensor
wiring 22 is narrower than the line width of the touch sensor
wiring 22 shown in FIG. 4 and FIG. 5.
Specifically, in the configuration shown in FIG. 5, the touch
sensor wiring 22 is in contact with the second insulating film 46
on both sides of a region in contact with the counter electrode 21
on the upper surface (the surface on the counter electrode 21 side)
of the touch sensor wiring 22. On the other hand, in the
configuration shown in FIG. 18, a touch sensor wiring 22A is in
contact with the second insulating film 46 only on one side of the
region of the upper surface of the touch sensor wiring 22A in
contact with the counter electrode 21.
For example, as shown in FIG. 18, in a case where the adhesion
between the touch sensor wiring 22A and the second insulating film
46 is poor, having a configuration in which the touch sensor wiring
22A is in contact with the second insulating film 46 only on one
side rather than both sides reduces the surface area of the
interface between the touch sensor wiring 22A and the second
insulating film 46, thus improving the adhesion.
The embodiments described above are merely examples for
implementing the present invention, thus, the present invention is
not limited to the embodiments described above, and it is possible
to appropriately modify and implement the embodiments described
above without departing from the spirit of the invention.
For example, the TFT 42 is not limited to being a bottom gate type
and may be a top gate type. In addition, the semiconductor film 42b
may be an oxide semiconductor film such as indium tin zinc oxide
(ITZO), or may be a film formed of a semiconductor material such as
amorphous silicon, low temperature poly silicon (LTPS), or
continuous grain silicon (CGS).
The second insulating film 46 between the touch sensor wiring 22
and the counter electrode 21 may be formed of four or more
insulating film layers.
In the manufacturing processes shown in FIG. 6 to FIG. 8, after the
TFT 42 is formed on the glass substrate 40 and the first insulating
film 44 and the planarizing film 45 are formed on the TFT 42 (refer
to FIG. 6(a)), a plasma treatment was performed (refer to FIG.
6(b)) before arranging the mask 61 (refer to FIG. 6(c)). However,
the plasma treatment is not limited to this timing, and the plasma
treatment may be performed after peeling off the mask 61 (refer to
FIG. 6(e)) before the transparent electrode film 62 and the metal
film 63 are formed (refer to FIG. 6(f)).
REFERENCE SIGNS LIST
1 ACTIVE MATRIX SUBSTRATE 2 COUNTER SUBSTRATE 3 LIQUID CRYSTAL
LAYER 10, 10A, 10B TOUCH PANEL-ATTACHED DISPLAY DEVICE 21 COUNTER
ELECTRODE 22, 22A TOUCH SENSOR WIRING 31 PIXEL ELECTRODE 42 TFT
(DISPLAY CONTROL ELEMENT) 42a GATE ELECTRODE 42b SEMICONDUCTOR FILM
42c SOURCE ELECTRODE 42d DRAIN ELECTRODE 43 GATE INSULATING FILM 44
FIRST INSULATING FILM 45 PLANARIZING FILM 46 SECOND INSULATING FILM
46a, 46c INSULATING FILM FORMED OF FIRST MATERIAL 46b, 46d
INSULATING FILM FORMED OF SECOND MATERIAL 46e INSULATING FILM
FORMED OF THIRD MATERIAL 47 CONDUCTIVE FILM
* * * * *